Description: This shrimp has the typical
extremely short rostrum
characteristic of many crangonids (photo).
The carapace
is smooth and has a median dorsal spine but no submedian spine (photo).
Abdominal segment 6 has no longitudinal dorsal carinae
(photo) but the underside does have a median
sulcus
(photo). Abdominal segment 5 has no
spines on the upper posterolateral margins (photo).
The inner flagellum
of antenna 1 is longer than the outer flagellum. The antennal
scale is more than twice as long as wide, has a narrow lamella,
and its spine
is as long as or longer than the lamella (photo).
The scale is shorter than the telson.
Length to 6.5 cm.

How to Distinguish from Similar Species: Crangon
nigricauda has a shorter antennal scale and spine and is much less
slender.

Geographical Range: Bering Sea to San Diego,
CA

Depth Range: Intertidal to 275 m.
This species seems to be found more often in deeper, shelf waters than
near the intertidal zone.

Habitat: Crangonids often live on sand,
which they often burrow into.

Biology/Natural History: This shrimp is
one of the crangonids I most commonly find in 100 m depth trawls in the
San Juan Channel. Crangonids are often parasitized by bopyrid isopods
such as Argeia. Crangonids are active predators, eg. on polychaetes.
In Puget Sound some shrimp appear to be hybrids between C alaskensis
and C. nigricauda.

The carapace
is smooth and has one median spine a short distance behind the eyes, as
can be seen silhouetted in this view from the right side.

The 5th segment of the abdomen (left full segment in this photo) has
no spines on the posterolateral margin (right edge of segment),
and the 6th segment (middle of photo) has no longitudinal dorsal ridge.
The uropods
and telson
are to the right.

The ventral side of abdominal segment 6 has a median
groove, visible as the light-colored area in this photo.

The antennal
scale of the second antennae, being held out by my finger in this photo,
is more than twice as long as wide and the spine on the end (left side
of scale) is longer
than the flatter
lamella (right side of end of scale)

A view of the whole, live animal ffom which the parts above were photographed.
Photo by Dave Cowles, July 2005